Scyllo-Inositol is one of the stereoisomers of myo-inositol (MI) and is a compound widely found in animals and plants. scyllo-Inositol is expected for applications such as a therapeutic drug for Alzheimer's disease, a raw material for the synthesis of bioactive substances, and a raw material for the synthesis of liquid crystal compounds. While myo-inositol is supplied at low cost, scyllo-inositol is an expensive compound. Hence, a variety of studies have been carried out on a method of manufacturing scyllo-inositol involving the use of myo-inositol as a raw material.
Examples of the method of manufacturing scyllo-inositol by use of a chemical synthesis technique include a method involving providing scyllo-inositol by oxidizing myo-inositol with a platinum catalyst to afford 2-keto-myo-inositol (scyllo-inosose) and subsequently subjecting the resultant to esterification followed by reduction and hydrolysis.
Further, there is disclosed, as a method of converting myo-inositol to scyllo-inositol, a method involving the use of a bacterium belonging to the genus Pseudomonas and a bacterium belonging to the genus Acetobacter separated from the nature. The method involves providing scyllo-inositol by producing 2-keto-myo-inositol from myo-inositol using the above-mentioned bacterium and subjecting 2-keto-myo-inositol to chemical reduction (Patent Literature 1).
Strains capable of producing a small amount of scyllo-inositol from myo-inositol were obtained from bacteria belonging to the genus Acetobacter and the like (Patent Literature 2). It is known that an enzyme for stereospecifically reducing 2-keto-myo-inositol to scyllo-inositol in an NADPH-dependent manner is functioning in those strains.
There is a report that a strain capable of efficiently producing D-chiro-inositol from myo-inositol was obtained by the genetic modification of genes involved in inositol catabolism in a bacterium belonging to the genus Bacillus (Patent Literature 3 and Non Patent Literature 1). Such strain (strain YF256) lacks the iolE gene and the iolR gene involved in inositol catabolism.    [PTL 1] JP 3981597 B2    [PTL 2] WO 2005/035774 A1    [PTL 3] JP 2006-141216 A    [NPL 1] Appl Environ Microbiol. 2006 Feb.; 72(2): 1310-5.